Porous sorbent materials such as adsorbent carbon, activated carbon, silica gel, alumina, polyester resins, zeolites or zeolite-like materials, and mixtures thereof can be effective in removing a wide spectrum of gas phase constituents from mainstream cigarette smoke when incorporated in cigarette filters. However, their lack of selectivity between smoke constituents may cause reduced shelf life and poor smoke subjectives. To improve filtration performance in cigarette filters, activated carbon, silica gel, and other porous substrates can be modified with chemical reagents that can target specific smoke constituents.